Extraction and Characterization of Organic Matter from Surface Waters (Reservoir of Keddara in Algeria)

Abstract

The combined XAD-8 and XAD-4 resin procedure for isolating dissolved organic solutes from Keddara reservoir in Algeria was found to isolate 65 % of total organic carbon (TOC). Of the 45 % of solute adsorbed onto XAD-8 resin, 34 % was in the form of fulvic acids, and 11% humic acids. Approximately 19 % of the hydrophilic solutes were adsorbed onto XAD-4 resin. Characterization experiments have shown that the three isolated fractions have a low apparent molecular weight investigated by ultrafiltration and fluorescence and low aromaticity as shown by the results of UV-absorbance, the formation potential of total organic halogens (reactivity with chlorine) and the polyhydroxyaromatic (PHA) determined by pyrolysis gas chromatography/mass spectrometry (GC/MS) which show that the isolated fractions are aliphatic as well as aromatic. The low molecular weight and the low aromaticity compared with literature data are due to coagulation and sedimentation of NOM with high molecular weight, which occur naturally in the reservoir. The Keddara reservoir, with low hydraulic loading area and long detention times receiving water with low NOM and high in hardness can be expected to be very effective coagulation and sedimentation basins.